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Figure 10-4. OPERATION OF THE MASTER TRANSMITTER INDICATOR Sub Log Home
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Figure 10-4. OPERATION OF THE MASTER TRANSMITTER INDICATOR
1 FORWARD MOTION OF THE SHIP CREATES DYNAMIC PRESSURE IN THE BELLOWS.  BELOWS RAISES THE ROD AND MOVES MAIN BALANCE ARM.
2 MAIN BALANCE ARM CLOSES CONTACT TO POWER MOTOR.
3 POWER MOTOR DRIVES CAM, POINTER AND SELF-SYNCHRONOUS TRANSMITTER
4 MAIN FORCE ARM PIVOTS AS THE CAM REVOLVES, STRETCHING SPRING WHICH EXERTS AND OPPOSITE FORCE ON THE MAIN BALANCE ARM.
5 AUXILIARY BALANCE ARM SPRING AIDS THE MAIN FORCE ARM SPRING IN OPPOSING THE PRESSURE ON THE MAIN BALANCE ARM.
6 AS THE CAM CONTINUES TO ROTATE, THE MAIN FORCE ARM SPRING IS STRETCHED STILL MORE. AS LONG AS CONTACT IS MAINTAINED TO THE POWER MOTOR BY THE BELLOWS PRESSURE, THE CAM WILL CONTINUE TO INCREASE THE TENSION ON THE MAIN FORCE ARM SPRING.  WHEN THE SPRING TENSION JUST OVERCOMES THE BELLOWS PRESSURE, THE CONTACT ON THE MAIN BALANCE ARM WILL BE RETURNED TO NEUTRAL AND THE CAM WILL STOP ROTATING.  THE SYSTEM WILL THEN BE IN BALANCE AND THE POINTER WILL INDICATE THE SPEED OF THE SHIP.
7 LEAD SCREW IS DRIVEN FROM THE POWER MOTOR, TRANSMITTING MOTION TO THE TOP GROUP OF ASSEMBLIES WHICH CONVERT SPEED INTO DISTANCE TRAVELLED.
8 SELF-SYNCHRONOUS TRANSMITTER IS DRIVEN BY FOLLOWER AND TRANSMITS DISTANCE TRAVELLED TO DISTANCE INDICATORS.
9 FOLLOWER IS FRICTION-DRIVEN BY THE CONTANT SPEED DISK, AND IS MOVED ACROSS THE FACE OF THE DISK BY ITS LEAD SCREW.  360 REVOLUTIONS OF THE FOLLOWER WILL INDICATE 1 MILE ON THE DISTANCE INDICATOR.  SINCE THE FOLLOWER LEAD SCREW IS DRIVEN FROM THE POWER MOTOR WHICH IS CONTROLLED BY THE SPEED CAM, THE POSITION OF THE FOLLOWER ON THE CONSTANT SPEED DISK WILL BE DETERMINED BY THE POSITION OF THE CAM AND SPEED POINTER.
10 DISK IS DRIVEN BY A SYNCHRONOUS MOTOR AT A CONSTANT SPEED OF 60 RPM.
11 DIFFERENTIAL, RHEOSTAT, AND FOLLOW-UP MOTOR PROVIDE ADDITIONAL TORQUE TO THE TRANSMITTER SO THAT IT WILL OPERATE AT THE SAME REVOLUTIONS PER NAUTICAL MILE AS THE FOLLOWER WHEN EXTRA LOADS ARE APPLIED, SUCH AS ADDITIONAL REPEATERS, D.R.T. AND D.R.A. SYSTEMS.
12 CAM HS MOVED THE MAIN FORCE ARM TO A POINT WHERE THE MAIN FORCE ARM SPRING HAS OVERCOME THE BELLOWS PRESSURE ON THE MAIN BALANCE ARM, AND THE CONTACT HAS BEEN RETURNED TO NEUTRAL, STOPPING THE POWER MOTOR.
13 WHEN THE SHIP REDUCES SPEED, THE PRESSURE IN THE BELLOWS IS LOWERED, CAUSING AN UNBALANCED CONDITION IN THE INSTRUMENT, AND CAUSING THE CONTACT ON THE MAIN BALANCE ARM TO MOVE TO THE REVERSE CONTACTS OF THE POWER MOTOR.  THE CAM IS THEN REVERSED AND MOVES TO A POSITION WHICH WILL BRING THE SYSTEM INTO BALANCE AND THE CONTACT OF THE MAIN BALANCE ARM TO NEUTRAL, STOPPING THE POWER MOTOR.


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